Abstract:Vaccines based on the strain Sofjin of the Far-Eastern tick-borne encephalitis virus (TBEV) subtype have been used for TBE prophylaxis for over 50 years in Russia and neighboring countries. On the wide territory, where all known TBEV subtypes are circulating, the cultural, purified, concentrated, inactivated TBE vaccine Moscow has been shown to be safe and efficacious in a massive immunization. In the present work, we describe the genome of the vaccine strain Sofjin. We have shown that it differs from TBEV str… Show more
“…TBEV strains (Table 1 ) were described previously (Gritsun et al, 1997 ; Romanova et al, 2007 ; Zlobin et al, 2007 ; Kozlovskaya et al, 2010 ; Vorovitch et al, 2015 ; Chernokhaeva et al, 2016b ; Shevtsova et al, 2016 ). The viruses were stored at −70°C as a 10% mouse brain suspension or a culture supernate (CS) of infected PEK cells.…”
Section: Methodsmentioning
confidence: 99%
“…Preventive vaccination is a primary prophylactic tool against TBE. Inactivated, purified, concentrated vaccines for adults and children based on FE strains Sofjin (Elbert et al, 1980 ; Vorovitch et al, 2015 ), 205 (Safronov et al, 1991 ; Karpova et al, 1995 ), and Senzhang (Zhang et al, 2012 ; Xing et al, 2017 ) and on Eur strains Neudoerfl (Ecker et al, 1999 ; Loew-Baselli et al, 2011 ) and K23 (Ecker et al, 1999 ; Zent et al, 2003 ) are available. Clinical trials have demonstrated their immunogenicity (Vorob'eva et al, 1983 ; Pavlova et al, 1999 ; Amicizia et al, 2013 ; Vorovitch et al, 2017 ).…”
Tick-borne encephalitis (TBE), caused by the TBE virus (TBEV), is a serious public health threat in northern Eurasia. Three subtypes of TBEV are distinguished. Inactivated vaccines are available for TBE prophylaxis, and their efficacy to prevent the disease has been demonstrated by years of implication. Nevertheless, rare TBE cases among the vaccinated have been registered. The present study aimed to evaluate the protective efficacy of 4 TBEV vaccines against naturally circulating TBEV variants. For the first time, the protection was evaluated against an extended number of phylogenetically distinct TBEV strains isolated in different years in different territories. The protective effect did not strongly depend on the infectious dose of the challenge virus or the scheme of vaccination. All vaccines induced neutralizing antibodies in protective titers against the TBEV strains used, although the vaccines varied in the spectra of induced antibodies and protective efficacy. The protective efficacy of the vaccines depended on the individual properties of the vaccine strain and the challenge virus, rather than on the subtypes. The neutralization efficiency appeared to be dependent not only on the presence of antibodies to particular epitopes and the amino acid composition of the virion surface but also on the intrinsic properties of the challenge virus E protein structure.
“…TBEV strains (Table 1 ) were described previously (Gritsun et al, 1997 ; Romanova et al, 2007 ; Zlobin et al, 2007 ; Kozlovskaya et al, 2010 ; Vorovitch et al, 2015 ; Chernokhaeva et al, 2016b ; Shevtsova et al, 2016 ). The viruses were stored at −70°C as a 10% mouse brain suspension or a culture supernate (CS) of infected PEK cells.…”
Section: Methodsmentioning
confidence: 99%
“…Preventive vaccination is a primary prophylactic tool against TBE. Inactivated, purified, concentrated vaccines for adults and children based on FE strains Sofjin (Elbert et al, 1980 ; Vorovitch et al, 2015 ), 205 (Safronov et al, 1991 ; Karpova et al, 1995 ), and Senzhang (Zhang et al, 2012 ; Xing et al, 2017 ) and on Eur strains Neudoerfl (Ecker et al, 1999 ; Loew-Baselli et al, 2011 ) and K23 (Ecker et al, 1999 ; Zent et al, 2003 ) are available. Clinical trials have demonstrated their immunogenicity (Vorob'eva et al, 1983 ; Pavlova et al, 1999 ; Amicizia et al, 2013 ; Vorovitch et al, 2017 ).…”
Tick-borne encephalitis (TBE), caused by the TBE virus (TBEV), is a serious public health threat in northern Eurasia. Three subtypes of TBEV are distinguished. Inactivated vaccines are available for TBE prophylaxis, and their efficacy to prevent the disease has been demonstrated by years of implication. Nevertheless, rare TBE cases among the vaccinated have been registered. The present study aimed to evaluate the protective efficacy of 4 TBEV vaccines against naturally circulating TBEV variants. For the first time, the protection was evaluated against an extended number of phylogenetically distinct TBEV strains isolated in different years in different territories. The protective effect did not strongly depend on the infectious dose of the challenge virus or the scheme of vaccination. All vaccines induced neutralizing antibodies in protective titers against the TBEV strains used, although the vaccines varied in the spectra of induced antibodies and protective efficacy. The protective efficacy of the vaccines depended on the individual properties of the vaccine strain and the challenge virus, rather than on the subtypes. The neutralization efficiency appeared to be dependent not only on the presence of antibodies to particular epitopes and the amino acid composition of the virion surface but also on the intrinsic properties of the challenge virus E protein structure.
“…Для вакцинации использовали вакцину «Клещ-Э-Вак» (доза 0,5 мл, серия № 3.2009ж), представ-ляющую собой очищенную концентрированную суспензию инактивированного формалином вируса КЭ, сорбированного на алюминии гидроксиде. Действующим началом вакцины является специфический антиген штамма Софьин вируса КЭ (GenВank KC806252) [9]. Содержание белка Е в дозе вакцины составляет 0,90±0,15 мкг.…”
About 3,000 cases of TBE are registered annually in the Russian Federation. Vaccination is the main way to prevent the tick-borne encephalitis disease. Comparative study of the reactogenicity and immunogenicity of a new vaccine «Tick-E-Vac» was held. Volunteers aged from 16 years old were twice immunized with the vaccines «Tick-E-Vac» or «Encevir» derived from strains of Far East subtype of TBE virus, according to standard and emergency schemes. The clinical study was randomized, comparative, blind, and controlled. The frequency, intensity, time of occurrence, and duration of local and general reactions had been recorded. The titers of antiviral antibodies in ELISA had been determined to assess the immunological efficacy of vaccination. According to the results of the clinical study, the severity of local and general reactions in initial seronegative recipients was weak or moderate. The symptoms were usually manifested within 1-2 days after injection and persisted for not more than 4 days, after which time the symptoms disappeared. There was no statistically significant difference in the reactogenicity of the vaccines after the first and after the second injection. The reactogenicity also did not depend on the gender of recipients. After the first immunization, the level of seroprotection was not less than 43%; the average geometric titer of antibodies (GTA), not less than 1:200. After the second injection, the level of seroprotection reached 90-100%; GTA, not less than 1:500. The data on the reactogenicity and immunogenicity to the original seropositive recipients is not significantly different from the data for the initial seronegative recipients. The data indicate weak reactogenicity of the vaccines «Tick-E-Vac» and «Encevir». Double vaccination with an interval of 14 or 30 days leads to the formation of expressed immune response. Thus, differences in the level of seroprotection and in antiviral titers in the cases of the standard and emergency vaccination schedules are not statistically significant. The correlation between the development in recipients of local and general symptoms and the immunological efficacy of the vaccines has not been identified.
“…In the last two decades, considerable attention has been paid to TBE vaccine reactogenicity owing to a significantly increased number of vaccinated individuals, as well as a changing group composition and an expansion of the groups being vaccinated against TBE (e.g., children older than 1 year and elderly individuals) [6,7]. e most widely used TBE vaccine in Russia is licensed for people 3 years old and older and is the universal lyophilized "TBE vaccine Moscow" vaccine, which is based on the Sofjin strain of the FE subtype [1,8].…”
Up to 10,000 cases of tick-borne encephalitis are registered annually, 20% of which occur in children under 17 years of age. A comparison of the immunogenicity and safety between a new pediatric Tick-E-Vac vaccine based on the TBEV strain Sofjin and FSME-IMMUN Junior vaccine was performed in the Sverdlovsk region. The vaccine strains differ from strains of the Siberian subtype of TBEV that dominates in the region. The study was performed on 163 children aged 1 to 15, who received one of the vaccines according to either a conventional or rapid vaccination schedule. Immunogenicity was assessed based on the seroprotection rates and titers of virus-neutralizing antibodies. There were no significant differences in either the immunogenicity or reactogenicity of the pediatric vaccines based on strains of the Far Eastern or European subtypes of TBEV. Under both vaccination schedules, 30 days after the second injection, seroprotection rates were 100% for Tick-E-Vac and greater than 95% for FSME-IMMUN Junior, while the geometric mean titer of TBEV-neutralizing antibodies was at least 2,4 log10 (1 : 250) for either vaccine. Fourteen days after the second injection according to the rapid schedule, seroprotection rates were significantly lower, ranging from 50% to 63% regardless of the vaccine used. The observed adverse reactions were mild or moderate for both vaccines under both vaccination schedules, with total adverse event rates of less than 25%. Reactogenicity was not associated with the gender or age of the recipients. There were no statistically significant differences in the incidence of adverse reactions between the group of subjects who were baseline seronegative or seropositive. However, 14 days after the second vaccine injection according to the rapid schedule, a statistically significant difference in nAbs titers was identified between groups of children with and without reported reactions.
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